Single shot source size measurement of laser driven proton beams with active plasma lens

Using an active plasma lens we demonstrate a single-shot method to measure the energy-dependent source size of laser driven proton beams. The active plasma lens acts as an imaging system, yielding magnified proton beam spots at a distance of 1.5 meters behind the target. A simple Monte Carlo code is used to simulate the transport and retrieve the source size from the measurement. In the energy range of 3 to 7 MeV we show the measured proton beam source size is 210 to 60 micrometers, with an incident laser spot size of 52 micrometers and a peak laser intensity of 2 *1^-19 W /cm^-2.

The work was supported by Laboratory Directed Research and Development (LDRD) funding from Lawrence Berkeley National Laboratory provided by the Director, and the U.S. Department of Energy Office of Science Offices of High Energy Physics and Fusion Energy Sciences, under Contract No. DE-AC02-05CH11231. Work at BELLA was also supported by LaserNetUS (https://www.lasernetus.org/). J.H.Bin acknowledges financial support from the Alexander von Humboldt Foundation.